The present invention relates to an apparatus and a method for cleaning a pipe or a pipe system and a method for cleaning and verifying the cleanliness of the pipe or pipe system after completed cleaning.
Today, large transportable flush units are often used for cleaning pipes and pipe systems when there is no permanently installed equipment for pigging the pipe or pipe system. Such known flush units are large and cannot be handled without using cranes or the like because they require a high oil pressure and a substantial flow of liquid. This makes the work more complicated; it takes more time and requires more resources. Moreover, the known systems do not give satisfactory results when a high degree of cleanliness in the pipes is required, especially, for example, in the areas right against the pipe wall and at pipe joints.
Another problem with known systems is verification of cleanliness after the cleaning of the pipe or pipe system has been completed, when a certain standard of cleanliness is required. In many cases it is in fact a requirement that a satisfactory degree of cleanliness can be proven. This is, inter alia, the case in the petroleum industry. Eighty percent of all faults in hydraulic systems can be related to the particle cleanliness of the hydraulic oil. The formula for load-life calculations for ball and roller bearings is, inter alia, calculated based on particle concentration and water content of the oil. This is the basis for lifetime and reliability calculations for critical machine installations.
Systems for cleaning a pipe are already known from U.S. Pat. No. 5,444,886. This document teaches a system with a combined unit for launching and receiving a pig at each end of the pipe to be cleaned. The pig is driven through the pipe by a pressurised gas.
U.S. Pat. No. 6,391,121 B1 teaches a permanently installed system for cleaning the tubing of a heater where a combined launching and receiving unit is provided on either side of the heater. In addition, a parallel connection of the pipe and a pump is provided so that the pigs can be run back through the parallel connection.
It is therefore an object to provide a cleaning system that is substantially smaller and lighter than known systems and which therefore can be transported and handled with relative ease.
It is a further object of the invention to provide a cleaning system and a method for cleaning pipes and pipe systems which increase the degree of cleanliness after cleaning compared with existing systems, especially in problem areas of the pipes such as pipe joints and close to the surface of the pipes where turbulent flow is necessary to remove particles that are found on the interior walls of the pipe.
It is also an object to provide a cleaning system that is capable of verifying the internal cleanliness of the pipes after the cleaning operation.